編程之美區間覆蓋

昨天晚上快睡覺之前看了個 並查集。

下把基本的代碼上上

並查集找公用祖先，並查集壓縮路徑，並查集串連

#define MAX 100int pre[MAX];int find(int x){int y;int root;int temp;y=x;while(pre[x]!=x){x=pre[x];}root = x;while(pre[y]!=y){temp=pre[y];pre[y]=root;y=temp;}return root;}void join(int x,int y){int root_x = find(x);int root_y = find(y);if(root_x != root_y){pre[root_x]=root_y;}}

好了現在開始應對具體問題解決

#define MAX 100int pre[MAX];void init_set(){int i=0;for(i=0;i<MAX;i++)pre[i]=i;}int find(int x){int y;int root;int temp;y=x;while(pre[x]!=x){x=pre[x];}root = x;while(pre[y]!=y){temp=pre[y];pre[y]=root;y=temp;}return root;}void join(int x,int y){int root_x = find(x);int root_y = find(y);if(root_x != root_y){pre[root_x]=root_y;}}int main(){int x,y;int n;int i=0;int base_x,base_y;int father_x,father_y;while(1){scanf("%d%d",&x,&y);scanf("%d",&n);init_set();while(n--){scanf("%d%d",&base_x,&base_y);if(base_x > base_y){base_x = base_x^base_y;base_y=base_x^base_x;base_x=base_x^base_y;}for(i=base_x+1;i<=base_y;i++){join(base_x,i);}}father_x = find(x);father_y = find(y);if(father_x == father_y)printf("Yes\n");elseprintf("No\n");}}

並查集 好方法